Boil-tolerant cookware

Abstract

In some embodiments, a cooking utensil comprises a pot with a lid that divides a cooking chamber in the pot from a condensing chamber above the lid. To prevent boil-over, one or more openings in the lid and/or openings radially between the lid and the pot convey bidirectional flow between the cooking and condensing chambers. Boiling liquid/vapor foam from the cooking chamber flows upward through the opening to the condensing chamber. Upon subsequently flowing across an upper surface of the lid, the liquid/foam condenses and then returns through the opening to the cooking chamber. In some examples, the cookware includes both a mechanical seal and a liquid seal between the lid and the pot. In some embodiments, a single opening in the lid maximizes the lid's condensing surface while still allowing sufficient flow between the cooking and condensing chambers. Such a single opening also makes the cookware easy to clean.

The invention claimed is: 
     
       1. A cooking utensil comprising:
 a pot having a pot bottom, a pot rim, a pot sidewall, a cooling flange and an intermediate ledge, the pot sidewall encircling and adjoining the pot bottom, the cooling flange adjoining the pot rim, the intermediate ledge being interposed between the pot sidewall and the cooling flange; 
 a lid having a lid bottom, an outer periphery, a lid rim and a lower edge, the lower edge adjoining the lid bottom, the outer periphery adjoining the lower edge, the lid rim adjoining the outer periphery, the outer periphery being interposed between the lower edge and the lid rim, the lower edge and the lid rim being spaced apart by a certain axial dimension, the lid bottom defining an opening therethrough, the lid being selectively movable to a removed position and an employed position, the lid being spaced apart from the pot when the lid is in the removed position, the lid in the employed position is such that:
 a) the lower edge of the lid rests upon the intermediate ledge of the pot; 
 b) the lid rim is lower than the pot rim; 
 c) a cooking chamber is defined by the lid bottom, the pot bottom and the pot sidewall; 
 d) a condensing chamber is defined axially by the pot rim and the lid bottom and is defined radially by at least one of the lid and the cooling flange; and 
 e) the opening places the cooking chamber in open fluid communication with the condensing chamber; and 
 
 a condensing portion of the lid adjoining and encircling the opening, the condensing portion of the lid being part of the lid bottom, the condensing portion of the lid being less thermally conductive than the pot bottom; 
 wherein the lid includes a lid flange extending from the lower edge of the rim to the lid rim, the outer periphery of the lid being on the lid flange, an annular gap defined by the outer periphery of the lid and the cooling flange, the annular gap providing an average radial clearance between the cooling flange and the outer periphery. 
 
     
     
       2. The cooking utensil of  claim 1 , wherein the opening in the lid is a single hole through the lid bottom, and an entire remaining portion of the lid bottom beyond the single hole is impervious to fluid flow. 
     
     
       3. The cooking utensil of  claim 1 , wherein the single hole is nonconcentric with the outer periphery of the lid. 
     
     
       4. The cooking utensil of  claim 2 , wherein the single hole has a hole diameter, the cooking chamber has a cooking chamber volume, and a ratio of the cooking chamber volume divided by the hole diameter is within a range of 100 to 300 square centimeters. 
     
     
       5. The cooking utensil of  claim 1 , the annular gap being substantially concentric with the condensing chamber, the lid flange having a material radial thickness, the certain axial dimension between the lid rim and the lower edge being at least three times greater than the material radial thickness of the lid flange, the certain axial dimension between the lid rim and the lower edge of the lid being at least ten times greater than the average radial clearance between the cooling flange and the outer periphery of the lid. 
     
     
       6. The cooking utensil of  claim 5 , wherein the average radial clearance between the cooling flange and the outer periphery of the lid is less than 1.6 millimeters. 
     
     
       7. A cooking utensil comprising:
 a pot having a pot bottom, a pot rim, a pot sidewall, a cooling flange and an intermediate ledge, the pot sidewall encircling and adjoining the pot bottom, the cooling flange adjoining the pot rim, the intermediate ledge being interposed between the pot sidewall and the cooling flange; and 
 a lid having a lid bottom, an outer periphery, a lid rim and a lower edge, the lower edge encircling the lid bottom, the outer periphery adjoining the lower edge, the lid rim adjoining the outer periphery, the outer periphery being interposed between the lower edge and the lid rim, the lower edge and the lid rim being spaced apart by a certain axial dimension, the lid defining an opening therethrough, the lid being selectively movable to a removed position and an employed position, the lid being spaced apart from the pot when the lid is in the removed position, the lid in the employed position is such that:
 a) the lower edge of the lid rests upon the intermediate ledge of the pot, thereby creating a mechanically abutting seal between the lower edge and the intermediate ledge; 
 b) the lid rim is lower than the pot rim; 
 c) a cooking chamber is defined by the lid bottom, the pot bottom and the pot sidewall; 
 d) a first condensing chamber is defined axially by the pot rim and the lid bottom and is defined radially by at least one of the lid and the cooling flange; 
 e) a second condensing chamber is defined by an annular gap between the cooling flange of the pot and the outer periphery of the lid, the annular gap providing an average radial clearance between the cooling flange and the outer periphery, the second condensing chamber is substantially concentric with the first condensing chamber, the second condensing chamber provides an annular fluid seal above the mechanically abutting seal; 
 f) the opening places the cooking chamber in open fluid communication with the first condensing chamber; and 
 g) the certain axial dimension between the lid rim and the lower edge of the lid is at least three times greater than the average radial clearance between the cooling flange and the outer periphery of the lid. 
 
 
     
     
       8. The cooking utensil of  claim 7 , wherein the first condensing chamber extends radially out to the cooling flange. 
     
     
       9. The cooking utensil of  claim 7 , wherein the average radial clearance between the cooling flange and the outer periphery of the lid is less than 1.6 millimeters. 
     
     
       10. The cooking utensil of  claim 7 , wherein the lid includes a lid flange extending from the lower edge of the rim to the lid rim, the outer periphery of the lid being on the lid flange, the second condensing chamber being interposed between the lid flange and the cooling flange, the lid flange having a material radial thickness, the certain axial dimension between the lid rim and the lower edge being at least three times greater than the material radial thickness of the lid flange. 
     
     
       11. The cooking utensil of  claim 7 , wherein the opening in the lid is a single hole through the lid bottom, and an entire remaining portion of the lid bottom beyond the single hole is impervious to fluid flow. 
     
     
       12. The cooking utensil of  claim 11 , wherein the single hole is nonconcentric with the outer periphery of the lid. 
     
     
       13. The cooking utensil of  claim 11 , wherein the single hole has a hole diameter, the cooking chamber has a cooking chamber volume, and a ratio of the cooking chamber volume divided by the hole diameter is 100 to 300 square centimeters. 
     
     
       14. The cooking utensil of  claim 1 , wherein the lid bottom has a lower thermal conductivity than that of the pot sidewall.